XC6205 Datasheet, PDF (5/13 Pages) Torex Semiconductor – Low ESR Cap. Compatible Output On/Off Control

XC6205 Series
Preliminary
High Speed LDO Regulators
Low ESR Cap. Compatible, Output On/Off Control
! Operational Explanation
CE
ON/OFF
Control
each circuit
Current
Limiter
R2
R1
Voltage
Reference
VIN
VOUT
VSS
Output voltage control with the XC6205 series :
The voltage divided by resistors R1 & R2 is compared
with the internal reference voltage by the error amplifier.
The P-Channel MOSFET, which is connected to the
VOUT pin, is then driven by the subsequent output
signal. The output voltage at the VOUT pin is controlled
& stabilized by a system of negative feedback.
The current limit circuit and short protect circuit operate
in relation to the level of output current. Further, the IC's
internal circuitry can be shutdown via the CE pin's signal.
Low ESR Capacitors
With the XC6205 series, a stable output voltage is achievable even if used with low ESR capacitors as a phase
compensation circuit is built-in. In order to ensure the effectiveness of the phase compensation, we suggest that an
output capacitor (CL) is connected as close as possible to the output pin (VOUT) and the VSS pin. Please use an
output capacitor with a capacitance value as shown in the figure below. Also, please connect an input capacitor
(CIN) of 0.1µF between the VIN pin and the VSS pin in order to ensure a stable power input.
Recommended Output Capacitor Values
VOUT 0.9V ~ 1.2V 1.25V ~ 1.75V
CL
4.7µF
2.2µF
Current Limiter, Short-Circuit Protection
The XC6205 series includes a combination of a fixed current limiter circuit & a foldback circuit which aid the
operations of the current limiter and circuit protection. When the load current reaches the current limit level, the
fixed current limiter circuit operates and output voltage drops. As a result of this drop in output voltage, the foldback
circuit operates, output voltage drops further and output current decreases. When the output pin is shorted, a
current of about 50mA flows. However, when the input/output voltage differential is quite small, this current will be
about 200mA.
CE Pin
The IC's internal circuitry can be shutdown via the signal from the CE pin with the XC6205 series. In shutdown
mode, output at the VOUT pin will be pulled down to the VSS level via R1 & R2. The operational logic of the IC's CE
pin is selectable (please refer to the selection guide on page 2). Note that as the standard XC6205B type is ' High
Active/No Pull Down', operations will become unstable with the CE pin open. Although the CE pin is equal to an
inverter input with CMOS hysteresis, with either the pull-up or pull-down options, the CE pin input current will
increase when the IC is in operation. We suggest that you use this IC with either a VIN voltage or a VSS voltage
input at the CE pin. If this IC is used with the correct specifications for the CE pin, the IC will operate normally.
However, supply current may increase as a result of through current in the IC's internal circuitry.
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